A theoretical investigation of structural, electronic and optical properties of bulk copper nitrides

JOURNAL OF ALLOYS AND COMPOUNDS

卷:753

Article

Suleiman, Mohammed S. H.^1,2,3,4  Molepo, Mahlaga P.^1,2  Joubert, Daniel P.^1,2 

[1] Univ Witwatersrand, Sch Phys, Natl Inst Theoret Phys, ZA-2050 Johannesburg, South Africa

[2] Univ Witwatersrand, Mandelstam Inst Theoret Phys, ZA-2050 Johannesburg, South Africa

[3] Sudan Univ Sci & Technol, Dept Phys, POB 407, Khartoum, Sudan

[4] Imam Abdulrahman Bin Faisal Univ, Dept Basic Sci, Dammam, Saudi Arabia

关键词: DFT;    Crystal structure;    Electronic properties;    GW approximation;    Optical properties;    Copper nitride;   

DOI  :  10.1016/j.jallcom.2018.04.036

来源: Elsevier

【 摘 要 】

We present a first-principles density functional theory (DFT) study of the structural stability and electronic properties of bulk crystalline Cu4N, Cu3N, CuN and CuN2 in a set of twenty one different structural phases. By analysing the energetics of these systems, we show that DO9, B17 and C18 are the most stable phases in the parameter space considered for the Cu3N, CuN and CuN2 stoichiometric series, respectively. This study predicts that other Cu3N phases (i.e. RhF3 and DO2) have similar stability to DO9, and may be present during the nitridation process. These stable Cu3N phases are found to be indirect band-gap semiconductors with lower bulk moduli, whereas CuN(B17) preserves the metallicity and has a larger bulk modulus than pure Cu. Furthermore, the optical spectra of the experimentally synthesized Cu3N phase (DO9) is investigated by GW(0) calculations within the random phase approximation to the dielectric tensor. The obtained optical energy band-gap significantly improves the DFT values and agrees with some experiments. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

Free